I'm not a highschooler, and you don't understand the point.

If you're not an American younger than 35, this is probably something you don't understand because you didn't experience first-hand.

It's not a scenario where "your friends refuse to talk to you", it's "there are so many people to talk to, and there is a lot of friction around talking to this one person". You don't get the chance to become their friends in the first place.

If you can't get on iMessage, you can't be in iMessage group chats.

Similarly, if you don't have a cell phone, you can't text. If you don't have a landline, people can't call you. If you don't have the internet, you can't get on chatrooms. You wouldn't expect a teenager in the 90s to give up a landline in favor of living exclusively by handwritten letter.